package ch01.util;

import org.apache.log4j.Logger;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Map;

public class SimpleBeanConvertor {

    private static Logger logger = Logger.getLogger(String.valueOf(SimpleBeanConvertor.class));

    public static <T> T convert(HttpServletRequest request, Class<T> targetType) throws Exception{
        Map<String,String[]> params = request.getParameterMap();
        if(params.size() == 0) return null;
        T target = targetType.newInstance();
        Method[] allMethods = targetType.getMethods();
        if (allMethods != null && allMethods.length > 0) {
            for (Method allMethod : allMethods) {
                if (allMethod.getName().startsWith("set")){
                    Class[] args = allMethod.getParameterTypes();
                    if(args.length==1){
                        String paramName = allMethod.getName().substring(3,4).toLowerCase()+allMethod.getName().substring(4);
                        if (params.containsKey(paramName)){
                            try {
                                Object value = parseValue(params.get(paramName),args[0]);
                                allMethod.invoke(target,value);
                            }catch (ParseException e){
                                logger.debug("参数转换错误",e);
                                e.printStackTrace();
                                throw e;
                            }
                        }else if (Boolean.class == args[0] || boolean.class == args[0]){
                            allMethod.invoke(target,false);
                        }
                    }
                }
            }
        }
        return target;
    }

    private static Object parseValue(String[] value, Class type) throws Exception{
        if(String.class == type){
            return value[0];
        }
        if (java.util.Date.class == type){
            return (new SimpleDateFormat("yyyy-MM-dd").parse(value[0]));
        }
        if(boolean.class == type || Boolean.class == type){
            return true;
        }
        if (char.class == type || Character.class == type){
            return value[0].charAt(0);
        }
        if (int.class == type || Integer.class == type){
            return Integer.valueOf(value[0]);
        }
        if(short.class == type || byte.class == type || long.class == type || float.class == type
         || double.class == type)
            try {
                type=Class.forName("java.lang."+type.getName().substring(0,1).toUpperCase()+type.getName().substring(1));
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
        if (type.getName().startsWith("java.lang.") || type.getName().startsWith("java.math."))
            try {
                return type.getConstructor(String.class).newInstance(value[0]);
            } catch (Exception e) {
                e.printStackTrace();
            }
        throw new UnsupportedTypeException();
    }
}
